1. Field of the Invention
The present invention relates to a quick diffusion transfer process of forming color positive images using amidrazones and also to a photographic material for forming color positive images.
2. Description of the Prior Art
An amidrazone is the name given to the compounds investigated by S. Hunig et al and it is perhaps considered that the name is an abbreviation for amido-hydrazone. The amidrazone was, at first, defined to be shown by the general formula I or II ##EQU1## wherein X represents a hydrogen atom or ##SPC1##
That is, the compounds investigated first were those represented by the general formula I and it was reported that among those compounds, the compounds of the formulae ##SPC2##
Formed azo dyes by oxidative couplings with phenols, aromatic amines, or active methylene compounds using ferricyanide as an oxidizing agent [see, S. Hunig et al; "Agnew. Chemie," 70, 215(1958), "Ann. Chem.," 609, 160(1957), and ibid., 191(1959)]. Thereafter, many other compounds of the formula I and further open ring type amidrazones of the formula II described above were reported [see, "Ann. Chem., 651, 75(1962), etc.]. As the practical examples of the compounds of the formula II, the following compounds were shown: ##SPC3##
Furthermore, it was discovered that the compounds shown by the following formulae, which were considered to be amino-guanidine compounds, formed azo dyes by the same reaction as above; ##SPC4## On the other hand, J. Jeaken et al also made other investigations of the above-mentioned compounds at about the same time, that is the invention of the application of the compounds to photography was issued to Gevaert A. G. in 1961 as British Pat. No. 915,932 which was filed in 1959. In the patent the compounds of the general formula II indicated above are clasified into the aforesaid open chain type amidrazones represented by the formula II and the compounds of the general formula II wherein R.sub.1 and R.sub.2 form a ring and the latter type of the compounds was represented, for convenience, by the general formula III (the compounds of the aforesaid group IIb belong to the compounds of the formula III); ##EQU2## wherein ##EQU3## represents morpholine ##EQU4## piperidine ##EQU5## or piperazine ##EQU6## The compound having the following structure which has hydrazones at both ends of the piperazine ring is also included in the group of the formula III; ##EQU7##
Furthermore, the following complicated compounds were added to the group of the heterocyclic amidrazones represented by the formula I; ##SPC5## ##EQU8## and ##SPC6##
Moreover, the scope of X was expanded to include, besides a hydrogen atom and ##SPC7##
Conh.sub.2, so.sub.2 --ch, so.sub.2 --nh.sub.2, ##EQU9## and SO.sub.2 --R (wherein R represents an alkyl group, an aryl group, a substituted alkyl group, or a substituted aryl group.)
In a conventionally known color positive system using those amidrazones, dyes are formed in thick photosensitive emulsion layers coated in superposed relationship, which makes it necessary to further fix and wash the emulsion layers after subjecting the emulsion layers to development and oxidative coloring (bleaching) processing.
Also, because in the color positive materials of a conventional amidrazone system, the whole sensitive dyes are left after processing, the thick layer of gelatin or other binder itself is colored and further part of the remaining sensitive dyes is adsorbed thereon. Still further, besides the desired dye image and unreacted couplers, considerable stains tend to be left caused by remaining red-brown silver sulfide which is imperfectly bleached or the contamination of the binder from many processing baths and thus the blank portion of the photosensitive material is apt to be stained.
Furthermore, the compound formed by the reaction of the intermediate oxidation product of a developing agent and the amidrazone, which is considered to be substantially colorless and stable, usually has a color to some extent and is liable to be left in the emulsion layers. Therefore, it has not been determined whether such a photosensitive material can be stored for a long period of time without being colored or discolored since the technique has not yet been sufficiently investigated.
In the conventional Polacolor system and other similar diffusion transfer color photographic systems (see, specifications of British Pat. Nos. 840,731 and 904,364), it is required to process the photosensitive materials in the complete dark and thus those conventional systems are inconvenient for practical use.